title: Comparison of single- or multifrequency bioelectrical impedance analysis and spectroscopy for assessment of appendicular skeletal muscle in the elderly.
abstract: Bioelectrical impedance analysis (BIA) is used to assess skeletal muscle mass, although its application in the elderly has not been fully established. Several BIA modalities are available: single-frequency BIA (SFBIA), multifrequency BIA (MFBIA), and bioelectrical impedance spectroscopy (BIS). The aim of this study was to examine the difference between SFBIA, MFBIA, and BIS for assessment of appendicular skeletal muscle strength in the elderly. A total of 405 elderly (74.2 ± 5.0 yr) individuals were recruited. Grip strength and isometric knee extension strength were measured. Segmental SFBIA, MFBIA, and BIS were measured for the arms and upper legs. Bioelectrical impedance indexes were calculated by squared segment length divided by impedance (L2/Z). Impedance at 5 and 50 kHz (Z5 and Z50) was used for SFBIA. Impedance of the intracellular component was calculated from MFBIA (Z250-5) and BIS (RICW). Correlation coefficients between knee extension strength and L2/Z5, L2/Z50, L2/RICW, and L2/Z250-5 of the upper legs were 0.661, 0.705, 0.790, and 0.808, respectively (P < 0.001). Correlation coefficients were significantly greater for MFBIA and BIS than SFBIA. Receiver operating characteristic curves showed that L2/Z250-5 and L2/RICW had significantly larger areas under the curve for the diagnosis of muscle weakness compared with L2/Z5 and L2/Z50. Very similar results were observed for grip strength. Our findings suggest that MFBIA and BIS are better methods than SFBIA for assessing skeletal muscle strength in the elderly.
authors.affiliation: Laboratory of Sports and Health Science, Kyoto Prefectural University of Medicine, Kyoto, Japan;
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Yamada
authors.forename: Yuya
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ikenaga
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yokoyama
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Yoshida
authors.forename: Taketoshi
authors.initials: T
authors.lastname: Morimoto
authors.forename: Misaka
authors.initials: M
authors.lastname: Kimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000502:physiology; D001132:Arm; D001823:Body Composition / Q000502:physiology; D058266:Dielectric Spectroscopy / Q000379:methods*; D017097:Electric Impedance; D005260:Female; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007717:Knee; D007866:Leg; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000473:pathology / Q000502:physiology*; D055948:Sarcopenia / Q000473:pathology / Q000503:physiopathology
keywords: bioelectrical impedance analysis; elderly; muscle strength; sarcopenia; skeletal muscle mass